Data were obtained from the 2008/09 New Zealand Adult Nutrition Survey, a nationally representative, cross-sectional survey of 4721 subjects aged ≥15 years. Self-reported diabetes and the 2010 American Diabetes Association cut-offs for HbA1c were used to define diagnosed diabetes, undiagnosed diabetes and prediabetes. Prevalence rates were calculated and age-specific diagnosed diabetes rates were compared with those from the Virtual Diabetes Register, which counts known diabetes cases as follows: individuals with diabetes are identified using the NHI from 6 databases with information about hospital admissions, attendance at diabetes outpatients or retinal screening, diabetes-specific medication prescriptions, laboratory HbA1c testing and mortality. Overall prevalence rates of diabetes and prediabetes were 7.0% and 18.6%, respectively. Diabetes was more prevalent in men (8.3%) than in women (5.8%) and among the obese (14.2%) compared with the normal-weight group (2.4%). Pacific people had the highest prevalence of undiagnosed diabetes (6.4%), followed by Māori (2.2%) and New Zealand European and Others (1.5%).
